If I have "NMS-ADV-5" (5 devices and 50 APs). And I want to use NetSight manage and monitor 3rd party wireless controller and 3rd party 50APs. In this case if we use NetSight to manage and monitor IdentiFi with 50APs, it is OK.
In the case of the IdentiFi Controller the APs are managed through the "Wireless Manager". This application does not support 3rd party wireless controllers so you'd have to monitor each AP by modeling them and in NetSight with either an SNMP poll, or ICMP poll. This would also use licenses as well so the NMS-ADV-5 won't be enough for the 3rd party wireless controller and 50 APs.
What you may be able to do is model the wireless controller in NetSight, and enable traps/syslog to the NetSight server and create alarms based on syslog messages or traps that are seen when an AP goes out of server. Much like the "AP out of service" alarm that is set up for the IdentiFi controller. This way if the 3rd party wireless controller identifies a problem with an AP and sends a syslog/trap to NetSight this can trigger an alarm.